Puttio. A nice experience for Put.io on iPad.
This app makes it super easy to use Put.IO. See AwesomePutIOApp.com for marketing jargon. It's built in Objective-C, is good readable code, but there's a lot of late-night code in here. You'll need Xcode 4.5 to compile. It uses Storyboards & ARC.
Licensed under a slightly modified BSD. I'd love Pull Requests, but app store submissions will be a rarity.